Limiting Flow on AC voltage - Grundfos 11 SQF 2 pump

Estragon

Maybe I'm missing something, but it seems to me a level sensor or float switch in the well is the simplest solution.  It would just open a relay on the AC generator output when the water level gets too low?

Dave Angelini

I am missing it also.... Just add more panels and tanks and use a float switch. This is what everyone does who does not like remote genset runs.

methods

Back from the Dead, necroThread
From Phone @ 4:20AM
First Post

I have the same or very similar Grundfos.  Here are some ideas

1). I did not hear anyone suggest routing some of the flow back down the well...  such that pressure and flow remain low.  

That is a VERY common way to manage pumps in other industries.  Bypass Valve, adjustable.



2). I read the manuals back to back years ago.  I remember de-rated charts for lower input power.  The pump can run on batteries, solar, DC power supply (presumably it will MPPT that to CC), AC 120, AC 240.

A variable CV-CC supply can be useful for experiments/testing - from those learning you might look into Meanwell Brand DC Brick (best value).  

Specifically a unit that does not have hiccup mode but instead provides Constant Voltage then Constant Current ("CV-CC Power Supply) - we use these as Lithium Chargers 
* Voltage +/- 10% (you select standard voltage)
* Variable current limit 0-100%
* Potted IP63 outdoor use
* Wide input range

MPPT will say it to the exact point where you are on current limit with CV, so you need a variable current limit flavor (tested)


3).  Buy the expensive controller.  

They use PLC (Power Line Communication) to talk down the wire.  You can turn it on and off that way...  but agreed that running something like a 42GPM pump on a 4.2GPM well results in draining it flat in 4.2min (lol)

Joking about the 42GPH, but the problem is real.  I can run my well dry in 3min flat but at half the flow rate it can run 24/7.


...  you may have guessed that I have the same issue.  What was your outcome OP?  My vote is for #1, but I have not proven it yet

4)  Buy a lower power pump, run it off of a DC-AC inverter from the solar setup.  I run Growatt 5000 ES units with Auto-Transformers.

That would put you in 48V territory, since even 240W is 20A on 12V...  after that wires start getting too big.

-methods

Dave Angelini

I think I PM'd the OP here years ago. I suggested this could all be solved by adding another water tank for peace of mind and keeping the cattle  happy with water.

It is one of the tools for offgrid. Redundancy and spares to get you away from using a generator or trucking water.

In the years since this post Grundfos has a few new options.

Miller_Ranch

Would a flow control valve work for your situation?

https://www.merrillmfg.com/products/flow-control-valves?variant=38031263400125&currency=USD&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&srsltid=AfmBOopemYvgrxjztAAq4KVQhpZhAgqS_tjcU6Z9jtg7Yg1DcEIdRze3YOw#